Justification:
This species is listed as Least Concern as its population is now growing rapidly and has not undergone the once-predicted declines. Despite its current population trend, the species remains potentially threatened by a number of factors. It tends to congregate in very large flocks, and suffered rapid declines in many parts of its range during the twentieth century because of hunting and other threats. Its roost sites are unprotected, large numbers died in a recent disease outbreak, and most importantly, the dry rice paddies where it feeds are being converted to vegetable farms and other uses. If evidence arises in the future that these threats have begun to drive a decline, the species may warrant uplisting.

Sibirionetta formosa breeds in eastern Siberia, Russia and occurs on passage in Mongolia and North Korea. It winters mainly in Japan, South Korea, which now holds the majority of the wintering population, and mainland China, and it is a rare winter visitor to Taiwan (China) and Hong Kong (China). In the early 20th century, it was one of the most numerous ducks in eastern Asia and flocks of many thousands were regularly reported, but a significant decline took place since the 1960s and 1970s. Since then however, wintering counts in South Korea have increased spectacularly from the c.20,000 located in the 1980s to a total of 658,000 recorded during simultaneous surveys in 2004, including c. 600,000 in the lower reaches of the Geum River, and a staggering total of c.1.06 million counted in January 2009 (Moores et al. 2010, N. Moores in litt. 2010), with concentrations of over 20,000 at six different sites (N. Moores in litt. 2010). In support of the view that a genuine population increase has taken place in South Korea, an analysis of counts conducted at 38 sites every year since 1999 indicate an increase from a yearly average of 11,533 in 1999-2003 to a yearly average of 314,994 in 2005-2009 (N. Moores in litt. 2010). The increase in the South Korean wintering population is believed to be linked an increase in newly reclaimed land as well as a decline in hunting pressure (Moores 1996, Moores et al. 2010, N. Moores in litt. 2010). In January 2006 a flock of 8,000-10,000 individuals was noted at the small Chongming Dongtan Ramsar Site in China (where the previous maximum was 300 individuals) and in 2006/2007 a flock of 50,000 was recorded at Yancheng National Nature Reserve; these represent the largest flocks recorded outside of South Korea in recent years (Zhang Kejia in litt. 2006, Zhang 2006). The total national population estimate has since been placed at 91,000 individuals (Cao et al. in prep.). The species has continued to increase its numbers and range in China (Lei Cao and M. Barter in litt. 2010), and a possibly slow increase in the population has been noted in Japan since the 1990s, albeit with some fluctuation in numbers (Hironobu Tajiri in litt. 2011).

The 2004 Asian Waterbird Census estimated the population in Korea at 455,000 individuals (D. Li in litt. 2005; Wetlands International 2006). A separate study in 2004 reported 658,000 individuals in Korea (Hansoo Lee in litt. 2004), but this could be an over-estimate. Further to this, Brazil (2009) has estimated national population sizes at <c.100 breeding pairs and c.50-10,000 wintering individuals in China and c.10,000-1 million breeding pairs in Russia.

It nests in open tussock meadows near water and in mossy bogs with clumps of willows Salix and larch Larix. It winters (in dense aggregations) on freshwater lakes, rivers, reservoirs, and farmland, often roosting on water during the day and feeding in fields during the night. It feeds on seeds and grain, water snails, algae and other water plants. The species arrives on its Korean wintering grounds from September, peaking through October and November and returning north in mid March/early April (Degtyarev et al. 2006).

Hunting was probably the main reason for its decline and is still a serious threat, particularly as it concentrates in large flocks on wetlands and arable land. However, hunting itself is now thought to be in decline (Moores 1996, Moores et al. 2010). In China and South Korea, birds are killed by poisoned grain; pesticide poisoning and pollution from agricultural and household wastes are thought to be a serious problem in the Geum River, South Korea (Degtyarev et al. 2006). Large declines in the numbers of Anatidae have occurred in Sanjiang plain and Poyang Hu, China, as a result of habitat loss to agricultural development and hunting. Wintering sites in South Korea are largely unprotected and threatened by the development of wetlands (N. Moores in litt. 2010); there has been a recent proposal for building the largest tourist development in northeast Asia on the Haenem reclamation site, a key site for wintering Baikal Teal (C. Moores in litt. 2005). Also, its habit of forming dense aggregations in winter renders the species susceptible to infectious diseases; 10,000 birds were recorded dead owing to avian cholera in October, 2002 (Degtyarev et al. 2006). The species suffers from disturbance at the Geum River with up to 12 incidences per day of disturbance from low flying aircraft (Degtyarev et al. 2006).

Conservation Actions UnderwayCITES Appendix II, CMS Appendix II. It is legally protected in Russia, Mongolia, Japan, South Korea, Hong Kong and some provinces in China; and is listed in the Red Data Books of South Korea, Russia and Yakutia (Degtyarev et al. 2006). Some important sites are protected areas, including Bolob lake and Khanka lake (Russia), the Geum River (South Korea [Degtyarev et al. 2006]) and Katano duck pond (Japan). Annual monitoring takes place in parts of its range (Degtyarev et al. 2006).

Conservation Actions ProposedContinue to study its population trend and establish more protected areas in its breeding grounds. Research its wintering status in China. Draft and implement a management plan for the wintering population in South Korea. Regulate hunting of all Anatidae species in China. Ensure its legal protection in all range states. Carry out efforts to reduce disturbance at key sites (N. Moores in litt. 2010). Garner the support of farmers for the conservation of this and other rice field species (N. Moores in litt. 2010).

Citation:

BirdLife International 2012. Sibirionetta formosa. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 02 August 2015.